Fluid purification system

ABSTRACT

A fluid purification system includes an elongated ultraviolet radiation emitting tube and independent fluid flow-controlling conduits. Each conduit is transparent to allow ultraviolet light emitted by the tube to enter the conduit, and defines a continuous, and is helically wound closely about the tube to insure that fluid flow through the conduits is exposed to the ultraviolet light. The system includes a filter having inlet and outlet ports. An end of each conduit is connected to one of the inlet and outlet ports of the filter. The system thus exposes the fluid to ultraviolet radiation both before and after the fluid is filtered.

This is a continuation of application Ser. No. 915,238, filed Oct. 3,1986, now U.S. Pat. No. 4,769,131, which is a continuation-in-part ofSer. No. 06/861,569, May 9, 1986, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to fluid purification systems and moreparticularly to fluid purification systems incorporating fluid exposureto both ultraviolet radiation and filtration.

2. Description of the Prior Art

In an attempt to provide high quality, potable drinking water, varioustreatment systems have been developed. Many such systems employactivated carbon filters, as a common treatment to remove odor, improvetaste, and remove chemicals, such as chlorine and chloroforms. However,carbon is a nutrient source that supports bacteria life and growth. As aresult, unless these filters are replaced frequently, the filtersthemselves provide a breeding ground for bacterial contamination. Thisbacteria is spread to the consumer as the water flows through thefilter, picking up the bacterial contamination and delivering thebacteria to the user.

It has been found that activated charcoal filters are so conducive tobacterial growth that filters not routinely replaced may provide morebacterial contamination to the water than the unfiltered water itself.In addition, the bacteria tend to occupy many of the absorptive sites inthe filter, reducing the filter's absorptive capacity and rendering thefilter ineffective for its intended purpose of purifying the water.

It is well known that exposure of water to ultraviolet radiation killsmicroorganisms and bacteria carried by the water. For this reason, manyconventional purification systems employ an ultraviolet sterilizationunit in series with a filtration unit.

For example, U.S. Pat. No. 3,550,782 to Veloz discloses a watersterilizer apparatus having a pair of parallel water carrying tubes, anda string of ultraviolet bulbs located between the tubes. A reverseosmosis unit is connected in series between the tubes, so that the waterflowing through the tubes is exposed to ultraviolet radiation bothupstream and downstream of the reverse osmosis unit. The Veloz '782patent states that the destruction of bacteria upstream of the reverseosmosis unit is desirable in order to protect the membrane of the unitagainst the accumulation of live bacteria. The filtered and sterilizedwater is stored in a large tank, from which water is drawn on demand.

The apparatus disclosed in the Veloz '782 patent may be suitable forsome applications, but is impractical for home, domestic use.

First, the tank used in the Veloz system may act as a further breedingground for microorganisms and bacteria, especially if the water remainsin the tank for any extended period of time. The tank is connected tothe faucet or water outlet, and bacteria may enter the tank through thefaucet. Also, the tank may require periodic flushing or cleaning, toremove bacteria laden water as well as sediment and the like.Furthermore, unless the tank is pre-sterilized prior to its use, orsterilized periodically during use (which would be an almost impossibletask for the consumer to undertake), any water fed to the tank from thesterilizer unit would quickly become contaminated with bacteria.

Second, the Veloz apparatus employs straight-line liquid flow tubesadjacent to the string of ultraviolet bulbs. Such a straight-lineconfiguration is impractical for installation in a private residence.

Size constraints of a home installed purification system are ofparamount importance. A purification system for use in a privateresidence should be a compact unit, easily installable by the consumer,within a kitchen sink cabinet or a bathroom vanity, for example.

The storage tank of the apparatus disclosed in the Veloz '782 patentrequires an inordinate amount of space. Furthermore, if the storage tankwere omitted from the Veloz system and the water was drawn on demanddirectly from the downstream tube, each tube would necessarily be ofsuch length that it would be impractical to install the system in aprivate home.

For example, assuming that the average flow rate of water consumed in aprivate residence is one gallon per minute, and assuming that the stringof bulbs provide an average of 90,000 microwatt seconds per squarecentimeter of ultraviolet radiation, then each tube of the Velozsterilization unit would have to be at least 6 feet long, with a crosssectional area of 0.2 square inches, to effectively kill the bacteriaand microorganisms carried by the water.

In addition, the apparatus disclosed in the Veloz '782 patent is notmaximally effective in sterilizing the water and maintaining the reverseosmosis filtration unit in a bacteria free state. This is believed to bedue to the straight-line path of the water through the flow tubes, whichprovide no turbulence to the water flow.

OBJECTS AND SUMMARY OF THE INVENTION

It is a principal object of the present invention to provide a waterpurification system which is an improvement over the apparatus disclosedin U.S. Pat. No. 3,550,782, and which overcomes the inherentdisadvantages of that system.

It is another object of the present invention to provide a waterpurification system which is capable of providing high quality,purified, potable water which is substantially free of all livingmicroorganisms as well as free of substantially all particulate matterand undesirable chemicals.

It is still another object of the present invention to provide a waterpurification system having the characteristic features described abovewhich is easily installed for domestic use, and inexpensive to purchaseand operate.

It is a further object of the present invention to provide a waterpurification system having the characteristic features described abovewhich is capable of easily being expanded or configured to satisfy anyparticular need.

It is yet another object of the present invention to provide a waterpurification system having the characteristic features described abovewhich is constructed for maximum water purification in a minimum-sizedunit.

It is a still further object of the present invention to provide a waterpurification system having the characteristic features described abovewhich combines ultraviolet radiation exposure and filtration in a mannerwhich minimizes bacterial growth in the filter medium.

It is yet another object of the present invention to provide a waterpurification system having the characteristic features described abovewhich substantially eliminates the delivery of system generatedbacterial contamination to the user.

It is a further object of the present invention to provide a waterpurification system having the characteristic features described abovewhich is extremely efficient in its operation.

In one form of the present invention, a fluid purification systemincludes two independent fluid flow-controlling conduits, each of whichdefines an independent fluid flow channel, which are spirally woundabout a substantial portion of an elongated, ultraviolet radiationproducing tube. Each of these conduits is made from an ultravioletpermeable material, so that the fluid flowing through the conduits willbe exposed to ultraviolet radiation emitted by the ultraviolet tube.Furthermore, both of these fluid flow-controlling conduits are connectedto a filter, with one conduit being connected to the inlet of the filterand the other conduit being connected to the outlet of the filter.

The circuitous path of the fluid flowing through the spirally woundconduits creates a turbulent flow, which ensures exposure of all ofmicroorganisms carried by the water to ultraviolet radiation.Furthermore, spirally winding the conduits allows them to be tightlypacked, which decreases the overall length of the ultraviolet tuberequired for sufficient exposure. Thus, the fluid purification system ofthe present invention assures that the water entering the filter ismaximally exposed to ultraviolet radiation prior to filtration, as wellas being maximally exposed to ultraviolet radiation a second time, afterpassage through the filter. It has been found that the configurationdescribed above provides a water purification system which overcomesmany disadvantages inherent in conventional purification systems, andattains a water delivery system capable of producing dependable,continuous, reliable potable water, virtually free of livemicroorganisms, particulate matter, chemicals, and odor. In addition,the system is equally useful for all fluids in which contaminantpurification is sought.

The present invention attains maximum ultraviolet radiation exposurewith the equipment being held to the minimum size. As a result, a systemcapable of providing high quality, potable water, or other fluid,virtually free of bacteria, particulate, and chemicals is attained, withits overall size being sufficiently small to be easily mounted in anydomestic situation in direct association with any desired water faucetor other fluid source.

By employing the present invention, it has been found that bacterialgrowth in the filter medium is virtually eliminated. It is believed thatthe present invention completely eliminates the food supply for themicroorganisms in the filter medium.

In the present invention, the fluid flowing through the system isexposed to ultraviolet radiation prior to entering the filtration zone.This kills most, if not all, live microorganisms in the fluid prior totheir reaching the filter. Furthermore, upon exiting the filter, asecond exposure of ultraviolet radiation is provided. In this way, anymicroorganisms which may have passed through the first exposure or whichhave been retained in the filter medium are killed prior to delivery ofthe fluid for use or consumption.

In addition, passage of airborne microorganisms into the filter mediumentering through the fluid delivery port is prevented, since allbacteria or microorganisms would have to pass through the ultravioletradiation prior to reaching the filtration zone. Consequently, the foodsupply for any microorganisms retained in the filter zone is cut off,due to the dual exposure of ultraviolet radiation, and the filter mediumis maintained substantially bacteria free.

A further feature of the present invention is the modularization of thepurification system of this invention into a sterilization section and afiltration section. In this way, additional sterilization sections andadditional filtration sections can be combined in any desiredconfiguration to customize a purification system for various uniquesituations.

For example, if specific microorganisms, such as giardia lamblia, whichare resistant to ultraviolet radiation, were known to be contaminatingthe water supply, additional sterilization sections would be added tothe purification system to provide the necessary ultraviolet exposure toassure that a high quality potable water product is attained. Similarly,if particular toxic chemicals were known to be in the water supply,additional filter sections would be added to the purification system toremove these toxic chemicals and provide the desired high qualitypotable water.

Preferred forms of the water purification system, as well as otherobjects, features and advantages of this invention, will become apparentfrom the following detailed description of illustrative embodimentsthereof, which is to be read in connection with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view, partially broken away, showing onepreferred form of the fluid purification system of this invention.

FIG. 2 is a side elevational view of the sterilizer section of the fluidpurification system shown in FIG. 1, with the side cover removedtherefrom.

FIG. 3 is a bottom plan view of the sterilizer section of the fluidpurification system shown in FIG. 1.

FIG. 4 is a side elevational view, partially broken away, showing thefilter section of the fluid purification system shown in FIG. 1.

FIGS. 5, 6 and 7 are schematic views showing various structuralarrangements in which the modularized fluid purification system of thisinvention can be employed.

FIGS. 8 and 9 are schematic, cross-sectional views showing alternateconfigurations for the fluid flow-controlling conduit means employed inthe fluid purification system of this invention.

FIG. 10 is a perspective view of an alternative, second embodiment ofthe present invention.

FIG. 11 is a perspective view of a third embodiment of the presentinvention.

FIG. 12 is a sectional view of the embodiment shown in FIG. 11 takenalong the lines 12--12 of FIG. 11.

FIG. 13 is a sectional view of the embodiment shown in FIG. 11 takenalong the lines 13--13 of FIG. 12.

FIG. 14 is a partial, exploded view of a fourth embodiment of thepresent invention.

FIG. 15 is a sectional view of the embodiment shown in FIG. 14 takenalong the lines 15--15 of FIG. 14.

FIG. 16 is a perspective view of a fifth embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1, one preferred embodiment of fluid purification system 20 ofthe present invention is shown. In this embodiment, system 20 comprisesa sterilization section 21 and a filter section 22.

Sterilization section 21 incorporates a housing 25 in which anelongated, ultraviolet radiation producing tube 26 is securely mountedand connected to electronic control means (not shown) to assurecontinuous production of ultraviolet radiation. In addition, in thispreferred embodiment, fluid flowcontrolling conduit means 27 arearcuately coiled about elongated tube 26 in juxtaposed, spaced radiationreceiving relationship therewith. As will be described in more detail,conduit means 27 includes first and second ultraviolet radiationtransmissible portions, which define first and second flow channels,respectively, for the passage of the fluid in tortuous paths about theperiphery of tube 26, and which further define a fluid inlet and a fluidoutlet for each of the first and second flow channels. Conduit means 27controls the fluid flow about tube 26 and assures that the fluid flowingtherethrough receives the requisite exposure to ultraviolet radiation.

Preferably, a radiation reflective shield 28 peripherally envelopesconduit means 27, in order to maximize the effectiveness of theultraviolet radiation as well as prevent or reduce the radiationreaching the outside area. Typically, due to its ease of installation,any reflective material which comprises a cylindrical shape or is easilyformed into a cylindrical shape is used for shield 28.

In the embodiment depicted in FIGS. 1 and 4, filter section 22incorporates a housing 30, in which filter means 31 is securely retainedand positioned. Furthermore, housing 30 incorporates bracket means 32,to securely affix filter section 22 to sterilizer section 21.

As is more fully detailed below, depending upon the particularcontamination contained in the fluid being purified, filter means 31comprises one or more of the following filter elements--particulatematter filtration, odor filtration, organic chemical filtration, etc.Typically, filter means 31 comprises an activated charcoal filter toimprove water taste by removing undesirable chemicals and suspendedparticles. However, any other type of filter may be employed, eitherindividually or in combination, in order to satisfy any particularrequirement.

As depicted in FIGS. 1, 2 and 3, one preferred embodiment of fluid flowcontrolling conduit means 27 comprises two, transparent substantiallyequal length tube members 33 and 34, each of which are spirally woundabout elongated, ultraviolet radiation producing tube 26 in direct,juxtaposed, spaced facing relationship therewith, extending alongsubstantially the entire length thereof. Preferably, the tube members 33and 34 are interleaved with each other, with each coil of tube member 33being adjacent to a coil of tube member 34. Although alternateconfigurations for the fluid carrying conduit means 27 are shown inFIGS. 10 to 15 and will be described in detail, the arcuately coiledembodiment depicted in FIGS. 1 and 2 is preferred for maximizing theexposure of the fluid travelling through the conduit means toultraviolet radiation, using a minimum tube length and a minimum overallsystem size.

Another principal aspect of the present invention is the construction offluid purification system 20 with one of the two portions of the fluidflow controlling conduit means 27 being employed to carry the fluidentering the system through a first exposure to ultraviolet radiation,followed immediately by passage of the fluid through filter 31 offiltration section 22. In addition, once the fluid has passed throughfilter 31, the fluid enters the other portion of the fluid flowcontrolling conduit means 27 for a second ultraviolet radiationexposure. Once this second exposure is completed, the purified fluid isdelivered directly to the outlet faucet or portal for immediate use.

In FIGS. 1, 2, 3 and 4, this preferred construction is shown with tubemeans 33 receiving the input fluid flow through portal/fitting 35 andcontrollably carrying the fluid about the arcuately coiled flow pathdefined thereby, assuring that the fluid flowing therethrough iscontinuously exposed to the ultraviolet radiation emanating from tube26. Upon reaching portal/fitting 36, which is the output of tube means33, the fluid is carried through a connecting tube 46 to filter inputportal/fitting 37.

Once the fluid has thoroughly circulated through filter means 31 offilter section 22, the filtered fluid is delivered to portal/fitting 38,and delivered therefrom to portal/fitting 44, which is the input portalto tube means 34. Preferably, exit portal/fitting 38 of filter section22 and input portal/fitting 44 of tube means 34 are constructed formating engagement. However, interconnecting tube means may be employedif desired.

Once in tube means 34, the fluid advances through the arcuately coiledflow path defined by tube means 34, wherein the fluid is exposed to theultraviolet radiation a second time, as the fluid again arcuately flowsalong the length of elongated ultraviolet radiation tube 26,continuously advancing while simultaneously peripherally circulatingthereabout. Once the fluid has passed through tube means 34, the fluidexits through portal/fitting 39 for direct delivery to the user.

Preferably, the purified fluid exiting portal 39 is delivered directlyto a faucet or other suitable means for immediate use. By eliminatingthe need for a storage or holding tank, such as used in the apparatusdisclosed in U.S. Pat. No. 3,550,782, wherein bacterial contaminationwould flourish, the purity of the fluid delivered to the user of thepresent invention is assured.

It has been found that by employing the present invention, purifiedfluid is obtained which is substantially free of all bacteria, organiccontaminants, particulates, odors, and other common, undesirablecontaminants. Furthermore, it has been found that by employing thepurification system 20 of this invention, filter longevity is attainedand contamination and bacterial breeding in the filter is virtuallyeliminated.

In order to determine the overall size that the fluid purificationsystem of the present invention must be to attain a purified fluid,substantially free of all live microorganisms, several factors must beconsidered. First of all, the flow rate of the fluid passing through thesystem must be established and, secondly, for the given flow rate, thetotal amount of ultraviolet radiation exposure required must beestablished.

In determining the ultraviolet radiation exposure required, the type offluid to be purified and the microorganisms commonly found in that fluidare established. For this analysis, typical drinking water has beenselected as the fluid, with the water containing contaminants typicallyencountered with drinking water. However, the resistance of variousmicroorganisms found in drinking water must be known.

In general, most bacteria are killed by exposures to ultravioletradiation ranging between about 16,000 and 20,000 microwatt seconds persquare centimeter. In addition, viruses commonly found in drinking watersupplies are killed by ultraviolet radiation exposures ranging betweenabout 6,000 and 40,000 microwatt seconds per square centimeter. Moldspores require up to 60,000 microwatt seconds per square centimeter inorder to be killed, while parasites may require up to 200,000 microwattseconds per square centimeter or more of ultraviolet radiation beforesuch parasites are killed. In view of these statistical averages, adesign objective of 90,000 microwatt seconds per square centimeter wasestablished as the total ultraviolet radiation exposure to which thewater passing therethrough should be exposed. However, if desired, ahigher exposure can be attained in a variety of ways, such as reducingthe flow rate or adding sterilizing sections, as detailed herein.

With this exposure rate established, the water flow rate was determined.Since a flow rate of one gallon per minute is practical for mostdomestic water sources, this rate was employed to establish the overallsize of sterilization section 21 of fluid purification system 20.

Using these criteria, along with the known output of ultravioletradiation producing tubes, it was found that each tube member 33 and 34should have a length of at least 6 feet with a cross-sectional area ofabout 0.2 square inches. With these design goals in mind, it wasestablished that an ultraviolet radiation producing tube having anoverall length of 15 inches, with an illuminated area of about 13.5inches, provided the desired axial length for accommodating thepreferred lengths of interleaved, spirally wound tube members 33 and 34.

As shown in FIGS. 1, 2 and 3, the preferred embodiment of sterilizingsection 21 of fluid purifying system 20 also incorporates tubesupporting walls 40 and 41, which peripherally surround and supportinglyretain a portion of the mounting ends 42 of ultraviolet radiationproducing tube 26. As is well known in the art, ends 42 of tube 26incorporate prong contacts extending therefrom, which are interconnectedwith support plugs 43 mounted to housing 25, providing the requiredelectrical connection.

In addition, in this preferred embodiment, front wall 45 is removablyattached to housing 25 by screw means. In this way, wall 45 can beeasily removed, whenever necessary in order to change ultravioletradiation producing tube 26. Once wall 45 has been disconnected fromhousing 25, one end of tube 26 is automatically disconnected and can bequickly and easily removed from supporting engagement with walls 40 and41 and then replaced by a new tube. In this way, the efficient operationof sterilization section 21 of this invention can be easily maintained.

If desired, housing 25 may incorporate a removable side wall panel 52.In this way, access to the interior of housing 25 would be easilyattained.

In the preferred embodiment, all of the electronics required to operatesterilizing section 21 are mounted directly below housing 25, preferablynested within supporting bracket assembly 47. As shown in FIGS. 2 and 3,included within bracket assembly 47 is a transformer 48 which controlsthe requisite voltage output for properly driving the ultravioletradiation producing tube 26. In addition, fuse means 49 and an on/offpower control switch 50 are included. Any other desired electronicscould be incorporated in this zone, including such other optional itemsas light means (not shown) for providing a positive illuminationindication that the system is turned on and properly powered.

Bracket assembly 47 is mounted to the lower wall of housing 25 ofsterilizer section 21. In the preferred embodiment, bracket assembly 47comprises a side wall in which holes are formed in order to facilitatethe installation of fluid purifying system 20 of the present inventionto an abutting support wall. If desired, mounting holes may be formed inthe opposed wall of bracket assembly 47, or bracket assembly 47 may bemounted with the mounting hole containing portion thereof aligned witheither the right side or the left side of housing 25 of sterilizationsection 21. In this way, a universally adaptable mounting system isachieved.

In another preferred embodiment, fluid purifying system 20 of thepresent invention incorporates ultraviolet radiation level sensing meansand cooperating alarm means, in order to inform the user whenever thelevel of ultraviolet radiation falls below the level required to killthe microorganisms passing therethrough. Preferably, ultravioletradiation sensing means 53 is mounted directly adjacent on of the fluidflow controlling conduit means 27. This position is preferred since, inthis way, sensor 53 senses both the ultraviolet radiation output of tube26, as well as the amount of ultraviolet radiation passing through fluidflow-controlling conduit means 27.

In addition, sensor means 53 is connected to an alarm means 54, in orderto provide a positive, recognizable indication to the user that a faultcondition exists. Alarm means 54 may comprise a sound producing device,such as a horn or bell, in order to audibly warn the user that a faultcondition exists. If desired, alarm means 54 may comprise visualindicating means, such as a light, which is illuminated or constructedto flash whenever a fault condition is found. Furthermore, a combinationof both alarm types could be employed.

Although ultraviolet radiation sensor 53 may be positioned directlyadjacent to ultraviolet radiation producing tube 26, the preferredposition is directly adjacent to one of the fluid flow-controllingconduit means 27. This position is preferred since, in this way, sensor53 will sensor both a reduction in the ultraviolet radiation produced bytube 26, as well as a reduction in the ultraviolet radiation passingthrough fluid flow-controlling conduit means 27. As a result of thisconstruction, in addition to reduced output from tube 26, a faultcondition will be recognized and identified if the fluid passing throughfluid flow-controlling conduit means 27 comprises a colloidal suspensionor other concentrated particulate matter which prevents the requisitelevel of ultraviolet radiation from passing through conduit means 27.

This is particularly important when the system is installed to purifydrinking water, since heavily soiled, or particle-laden water may not becapable of being completely purified using the sizing of the systemconstructed for conventional water sources. With this system, the useris provided with a positive indication that the fluid passing throughpurifying system 20 has an abnormal condition which might be incapableof being fully purified.

In the preferred embodiment, fluid sterilization system 20 of thepresent invention is constructed with sterilizer section 21 and filtersection 22 being completely modularized, in order to allow any desiredconfiguration or component interconnection required for specificapplication requirements. In FIGS. 2 and 3, sterilizer section 21 isdepicted in detail, as described above, with the section beingconstructed for ease of use as a separate, modular element.

In FIG. 4, a detailed view of filter section 22 is shown, with housing30 peripherally surrounding and containing removable filter element 31clearly shown therein, with section 22 constructed for ease in use ofany particular desired construction or arrangement.

In FIGS. 5-7, various alternate configurations of the modularized systemof this invention are shown. In FIG. 5, two sterilizer sections 21A and21B are shown cooperatingly interconnected with a single filter section22. A system of this nature would provide ultraviolet radiation exposureof about 180,000 microwatt seconds per square centimeter, thereby beingcapable of assuring the elimination of most known bacteria, viruses,spores, and parasites. As a result, in a particular application wherehigh levels of bacteria are present or well known, more resistantmicroorganisms have been detected, a system as shown in FIG. 5, with twosterilizing sections being employed, would provide the desired fluidpurification.

In FIG. 5, the preferred interconnection method for the dual sterilizersections is shown. As depicted, the fluid entering sterilizer section21A makes its first pass through section 21A, exits sterilizer section21A and enters sterilizer section 21B. Once in sterilizer section 21B,the fluid makes its first pass through sterilizer section 21B and passesfrom sterilizer section 21B into filter 22. After passage through filter22, the fluid passes for a second time through sterilizer section 21B,followed by a second pass through sterilizer section 21A, where thepurified fluid then exits for delivery to the user.

By employing this configuration, the fluid is exposed to a double doseof ultraviolet radiation both before filtration and after filtration.However, if for any particular purpose maximum exposure of the fluid toultraviolet radiation prior to filtration is considered desirable, thisdual sterilizer configuration could be constricted to allow the fluid topass through sterilizer section 21A in both directions, prior toentering sterilizer section 21B, where a third exposure to ultravioletradiation would be realized prior to passage of the fluid to filtersection 22. Of course, other arrangements can also be employed, as thesystem may be expanded to include any number of sterilizer sectionsrequired to meet particular needs.

In FIG. 6, an alternate arrangement for the modularized fluidpurification system 20 of the present invention is shown. In thisconfiguration, a single sterilizing section 21 is employed incombination with two filter sections 22A and 22B. A system constructionof this nature is employed in particular installations where a singlefilter has proven incapable of eliminating the particulate matter, odor,chloroform, or other organic or chemical contents which exists in thefluid supply. In addition, a system of this nature is employed where twodifferent types of filters, such as one activated charcoal and a papertype filter, are required to meet specific needs.

As shown in FIG. 6, the preferred arrangement of this embodiment bringsthe fluid supply into sterilizer section 21 and then directly fromsterilizer section 21 into filter 22A. After passage through filter 22A,the fluid passes into filter 22B for filtration therethrough. Oncethrough filter 22B, the fluid returns to sterilizer section 21 for itsfinal sterilization exposure before being delivered directly to theuser.

If desired, additional filters can be mounted to this system, in asimilar fashion, in order to provide further filtration of the fluid forparticular needs. However, regardless of the number of filters employed,a final passage of the fluid through sterilizer section 21 prior todelivery to the user is required, in order to attain the beneficialaspects of the present invention.

In FIG. 7, a final example of various alternate installations for fluidpurification system 20 of the present invention is shown. In thisconfiguration, two sterilizer sections 21A and 21B are employed alongwith two filter sections 22A and 22B. Although these sections could beinterconnected with each other in a variety of alternate ways, withoutdeparting from the scope of the present invention, FIG. 7 depicts theparticular configuration considered to be preferred. However, regardlessof the particular configuration employed, it is important to note thatin accordance with the present invention, the fluid must be exposed toultraviolet radiation prior to filtration, and must be exposed toultraviolet radiation again after the final filtration, just prior topassage to the user.

The preferred construction shown in FIG. 7 essentially represents theuse of two single filtration systems 20, as detailed above, which areconnected in series. As shown in FIG. 7, fluid passes throughsterilization section 21A, then through filter section 22A, back throughsterilization section 21A, as is done with a single fluid purificationsystem 20. However, in this construction, the fluid exitingsterilization section 21A passes through sterilization section 21B andthen through filter 22B. Once through filter 22B, the fluid makes afinal pass through sterilization section 21B and is then delivereddirectly to the user.

As is readily apparent from the alternate structural arrangementsdetailed above for constructing a fluid purification system inaccordance with the present invention, these particular constructionsare merely examples of numerous alternate construction arrangements thatcan be employed for the present invention. Consequently, theconstructions detailed above have been presented merely for exemplarypurposes, and are not in any way intended to limit the scope of thepresent invention.

In FIGS. 8 and 9, two alternate configurations for the fluidflow-controlling conduit means are shown. In FIG. 8, conduit means 27Ais depicted as a corrugated elongated, continuous tube, with the sidewalls thereof comprising a corrugated, varying diameter configurationalong the entire length thereof. It is believed that this corrugatedconduit configuration acts optically to enhance the transfer ofultraviolet radiation to the fluid passing therethrough by dispersingthe ultraviolet rays, due to the irregular shape of the sidewalls of thecorrugated tube.

In FIG. 9, another alternate construction for conduit means 27 is shown.In this configuration, the conduit means comprises an elongated,extruded construction in which two conduits are extruded in aside-by-side configuration, in order to further enhance the constructionof sterilizer section 21. Furthermore, in this configuration, theextruded conduit means 27B comprises a convex outer surface matinglyinterconnected with a concave outer surface. With this configuration,the concave surface is positioned about elongated, ultraviolet radiationproducing tube 26 in juxtaposed, spaced facing relationship therewith.In this way, the concave surface functions as a lens, and optically actsto deliver improved ultraviolet radiation transfer to the fluid passingtherethrough.

In addition to these two alternate conduit means, a variety of otherconduit means constructions can be employed. without departing from thescope of this invention. However, regardless of the tube configuration,the tube or conduit means must be formed from a material or acombination of materials which allows ultraviolet radiation to passthrough at least the radiation receiving walls thereof and into thefluid stream. Presently, ultraviolet permeable tubes formed from teflonare preferred. However, any other material having similar or betterultraviolet radiation transmission properties may be employed.

Alternate coil arrangements of the conduit means about elongatedradiation producing tube 26 can also be employed using the teaching ofthe present invention and without departing from the scope of thepresent invention. One such alternate configuration is wrapping the tubemeans longitudinally about elongated radiation producing tube 26, asopposed to an axial wrap, as shown in FIGS. 1 and 2. Such aconfiguration is illustrated by FIG. 10 of the drawings. Separate tubemeans 40 and 41 extend longitudinally along the ultraviolet producingtube 26 in a serpentine fashion, each tube means occupying a respective180° arc.

Another alternate configuration is shown in FIGS. 11 through 13. Acylindrically shaped jacket 43 surrounds the ultraviolet producing tube26. The jacket 43 is divided diametrically into two separate,non-communicative half-jackets 44 and 45, through which the fluid flows.

Each half-jacket 44 and 45 includes baffle means to provide aserpentine, turbulent flow to the fluid. The baffle means may be aseries of partition walls 46 arranged in spaced apart relationshiplongitudinally along the half-jackets 44, 45, with alternately spacedwalls 46 joined to and extending inwardly from opposite sides of itsrespective half-jacket. Each wall 46 does not extend entirely from oneopposite side of the half-jacket 44, 45 to the other, so as to allowfluid to flow through the half-jackets. Thus, the partition walls 46provide a tortuous path for the fluid, which maximizes the exposure ofmicroorganisms and bacteria carried by the fluid to ultravioletradiation emitted by the tube 26.

A further alternate conduit means is illustrated by FIGS. 14 and 15. Afluid impervious core 50 has formed therein a central bore 51 runninglongitudinally through it. The bore 51 is dimensioned to closely receivethe ultraviolet producing tube member 26, which is preferablycylindrical in shape. Formed in the inner surface 52 of the core 50defining the bore 51 is a continuous groove 53, which is preferablysemi-circular in cross-section. The groove 53 extends spirally in theinner surface of the core 50, from one axial end 54 of the core to theopposite axial end 55. The ultraviolet tube member 26 is so tightlyreceived by the bore of the core that it defines with the grooved innersurface a spiral flow channel for fluid passage surrounding theultraviolet tube member 26.

A further embodiment of the present invention is illustrated by FIG. 15.If desired, the tube members need not be interleaved, as shown inFIG. 1. Rather, separate spirally wound tube members 60, 61 may bewrapped about the ultraviolet radiation producing tube 26 and coaxiallypositioned adjacent to each other, end to end. Each tube member 60, 61preferably encircles one half of the ultraviolet tube's length.

In accordance with the present invention, a fluid flowcontrol system isconstructed to receive the incoming fluid and pass the fluid through anultraviolet radiation exposure prior to delivering the fluid to afilter. In addition, after filtration, the fluid is again exposed toultraviolet radiation immediately prior to delivering the fluid directlyto the user. By employing the fluid purification system of the presentinvention, potable water, virtually free of all bacteria, odor,chloroform, inorganic particulate matter, organic matter and livemicroorganisms, is provided.

Furthermore, by employing the present invention, a fluid purificationsystem is realized with which previously unreachable goals are attainedin a system which is compact and easily positioned and interconnected toexisting water or other fluid supply systems. One major aspect ofattaining this compact system is the use of a single ultravioletradiation producing tube about which is tightly coiled the fluid flowcontrolling conduit means, which provide both fluid flow into the filtermeans as well as fluid flow out of the filter means. This compactarrangement is further enhanced by the continuous interleaving of thetwo independent tube means which form the conduit means. In this way,using a single ultraviolet radiation producing tube, the requisite dualexposure to ultraviolet radiation is attached with simplicity, in aminimum, compact size.

As is apparent from the preceding detailed description of the preferredembodiments, the fluid purification system of the present inventioncontinuously produces potable water, virtually free of all livemicroorganisms, for immediate use, both consistently and for longer timeintervals than obtained with conventional systems. It is believed thatthe efficacy of the system of this invention is due principally to itsdual exposure of the fluid to ultraviolet radiation prior to filtrationand after filtration, and the maximization of exposure of themicroorganisms to the ultraviolet radiation producing tube. By employingthis invention, the filter is isolated from bacteria contamination,since both its inlet and outlet ports are connected directly to theultraviolet radiation exposure zones.

As a result of this unique configuration, live microorganisms do notenter the filter medium from the incoming fluid, since virtually all ofthe microorganisms in the fluid are killed during the initialultraviolet radiation exposure. Similarly, microorganisms cannot enterthe filter medium from the output side, since the output cf the filtermedium is connected directly to the second treatment zone of ultravioletradiation.

It is believed that by employing this dual radiation exposureconstruction with its resulting filter isolation, a filter previouslycontaminated by bacteria or other microorganisms will eventually becompletely cleaned of all live microorganisms.

It has been found that although the filter medium, in particularactivated charcoal, is a breeding ground for microorganisms, themicroorganisms require a constant supply of new microorganisms in orderto maintain a complete growth pattern. However, in the presentinvention, the filter is isolated, and live microorganisms are incapableof entering the filter, either from the input side or the output side.Consequently, microorganisms originally present in the filter mediumdie, and the filter ultimately becomes virtually bacteria-free and ismaintained virtually bacteria-free, since live microorganisms arecontinuously prevented from entering the filter medium.

Although illustrative embodiments of the present invention have beendescribed herein with reference to the accompanying drawings, it is tobe understood that the invention is not limited to those preciseembodiments, and that various other changes and modifications may beeffected therein by one skilled in the art without departing from thescope or spirit of the invention.

What is claimed is:
 1. A method for purifying liquids comprising thesteps of:supplying a liquid to be purified to a purifier inlet; exposingsaid liquid to be purified substantially immediately upon entering saidinlet to a predetermined quantity of ultraviolet radiation; passing theultraviolet-radiated liquid through a liquid purification filter;exposing the filtered liquid to a further predetermined quantity ofultraviolet radiation, said further ultraviolet radiation being providedto said liquid until said liquid is delivered to a purifier outlet foruse; providing an ultraviolet radiation transparent, helically coiled,conduit arrangement for passing said liquid from said inlet to saidfilter and from said filter to said outlet; selecting said predeterminedquantity of ultraviolet radiation and the size of said conduitarrangement to assure the extinction of undesirable microorganism,bacteria and viruses in said liquid; and isolating the liquid afterentry in said purifier inlet up to delivery to said purifier outlet froman external contamination source.
 2. A method for purifying liquidscomprising the steps of:supplying a liquid to be purified to a purifierinlet; exposing said liquid to be purified substantially immediatelyupon entering said inlet to a predetermined quantity of ultravioletradiation; passing the ultraviolet-radiated liquid through a liquidpurification filter; exposing the filtered liquid to a furtherpredetermined quantity of ultraviolet radiation; repeating the abovesteps in the recited sequence a predetermined number of times andwherein, in the final exposing step, the further ultraviolet radiationis provided to said liquid until said liquid is delivered to a purifieroutlet for use; providing an ultraviolet radiation transparent,helically coiled, conduit arrangement for passing said liquid from saidinlet to said filter and from said filter to said outlet; selecting saidpredetermined quantity of ultraviolet radiation and the size of saidconduit arrangement to assure the extinction of undesirablemicroorganisms, bacteria and viruses in said liquid; and isolating theliquid after entry to said purifier inlet up to delivery to saidpurifier output from any external contamination source.
 3. A liquidsterilization system comprising:means for providing emitted radiationincluding an elongated ultraviolet radiation emitting tube coupled to asource of electrical energy for emitting ultraviolet radiation; and apair of tubular liquid conduits, said conduits being helically coiled inpaired manner about said ultraviolet radiation emitting tube from oneend of said tube to the other with each coil of said helically coiledconduits laterally abutting adjacent coils to peripherally surroundsubstantially the entire length of said tube, each of said conduitshaving an inlet port at one end and an outlet port at the other and,said conduits being transparent to ultraviolet radiation to allowexposure of liquid flowing through said conduits to ultravioletradiation emitted by said tube; the size of said means for providingemitted radiation and the size of said conduits chosen to assureextinction of undesirable microorganisms, bacteria and viruses in liquidflowing through said conduits.
 4. The system of claim 3 wherein saidconduits being helically coiled in paired manner about said tube arearranged such that the coils of one conduit lie between coils of theother conduit except for the outermost coils at each end.
 5. The systemof claims 3 wherein the inlet port of one conduit is paired with andimmediately adjacent to the outlet port of the other conduit to allowfor opposing flow of liquid through said conduits.
 6. The system ofclaim 3 including means to couple the outlet of one conduit to the inletof the other conduit, said coupling means being arranged to prevententry of external contamination to said system.
 7. The system of claim 6wherein said coupling means includes means to couple the outlet of saidone conduit to the inlet of the other conduit through a further liquidprocessing means.
 8. The system of claim 3 wherein said conduits arecomposed of plastic and are cylindrical in cross section.
 9. A liquidpurification system comprising:an inlet to said system for supply ofliquid to be purified; means for emitting ultraviolet radiation; a firstconduit directly connected at one end thereof to said inlet forreceiving the liquid to be purified, said first conduit having an outletport at the other end and being transparent to the ultraviolet radiationemitted by said means for allowing said ultraviolet radiation to impingeon the liquid throughout flow of the liquid through first conduit;liquid processing means, coupled to said outlet port of said firstconduits for processing the irradiated liquid and for bringing it to anoutlet of said processing means after processing; a second conduitconnected at one end thereof to said processing means outlet forreceiving the processed liquid, said second conduit having an outletport at the other end and being transparent to the ultraviolet radiationemitted by said source for allowing said ultraviolet radiation toimpinge on the processed liquid throughout flow of the liquid throughsaid second conduit to the outlet port of said second conduit and asystem outlet directly connected to said outlet port of said secondconduit for delivering purified liquid to a user, said system beingarranged from inlet to outlet so as to prevent entry of external sourcesof contamination; said first and second conduits being helically woundabout said ultraviolet radiation emitting means and said first andsecond conduits and said ultraviolet radiation emitting means havingsuch size to assure the extinction of undesirable microorganisms,bacteria and viruses in the liquid upon exposure to said ultravioletenergy.
 10. The system of claim 9 wherein said source of ultravioletradiation is an elongated tube coupled to a source of electrical energyfor emitting ultraviolet radiation.
 11. The purification system of claim10 wherein said conduits are wound about said elongated tube in atortuous manner so as to provide substantial exposure of liquid flowingthrough said conduits to ultraviolet radiation and for providingturbulence to liquid flowing through said conduits to assure that theliquid passing therethrough is thoroughly exposed to said ultravioletradiation.
 12. The purification system of claim 11 wherein said firstand second conduits are helically coiled in paired manner about saidultraviolet radiation emitting tube from one end of said tube to theother with each coil of said helically coiled conduits laterallyabutting adjacent coils to peripherally surround substantially theentire length of said tube.
 13. The liquid purification system of claim11 wherein said first and second conduits are helically coiled insequential manner about substantially the entire length of saidultraviolet radiation emitting tube, each coil of said conduitslaterally abutting adjacent coils.
 14. The liquid purification system ofclaim 9 wherein said liquid processing means is a filter.
 15. A modularliquid purification system comprising:a system inlet; a system outlet; anumber of modular liquid sterilization systems, each having:means forproviding emitted radiation including an elongated radiation emittingtube coupled to a source of electrical energy for emitting ultravioletradiation and a pair of tubular conduits, said conduits being helicallycoiled in paired manner about said ultraviolet radiation emitting tubefrom one end of said tube to the other with each coil of said helicallycoiled conduits laterally abutting adjacent coils to peripherallysurround substantially the entire length of said tube, each of saidconduits having an inlet port at one end and an outlet port at the otherend, said conduits being transparent to ultraviolet radiation to allowexposure of liquid flowing through said conduits to ultravioletradiation and wherein the inlet port of one conduit is paired with andimmediately adjacent to the outlet port of the other conduit to allowfor opposing flow of liquid through said conduits; a number of modularfilter systems for filtering incoming fluid, each filter system having afilter inlet and a filter outlet; and means for interconnecting saidnumber of liquid sterilization systems and said number of filter systemsfor providing a liquid purification system having a closed liquid pathfrom system inlet to system outlet and for having fluid supplies to saidsystems only following exposure to ultraviolet radiation and for havingfluid filtered by said filter systems always subject to exposure toultraviolet radiation; the size of said means for providing emittedradiation and the size of said conduits chosen to assure extinction ofundesirable microorganisms, bacteria and viruses in liquid flowingthrough said conduits.
 16. The modular liquid purification system ofclaim 15 including at least two of said sterilization systems and onesaid filter system, said one conduits of said sterilization systemsbeing connected in series, said other conduits of said sterilizationsystems being connected in series and said filter system being connectedbetween the said two series connections.
 17. The modular liquidpurification system of claim 15, including at least two of saidsterilization systems and at least two of said filter systems, eachsterilization system having one of said filter systems being connectedbetween two conduits thereof, each sterilization system and filtersystem forming a first and second liquid purification system, whereinliquid purified by said first purification system is supplied to saidsecond purification system for further purification prior to delivery tosaid system outlet.